Multiple Outbound Caller IDs for Extensions

Creating Multiple Outbound Caller IDs for Extensions

There are times when one extension needs to present different outbound caller IDs based on the outbound trunk which is dynamically selected by the outbound rules of 3CX Phone System. In order to set this up follow the steps outlined in this guide.

Prerequisites

3CX Phone System V14 SP2 or up

Multiple Trunks per caller ID

The trunks MUST support “Originator Caller ID” (Clip No Screening), if there is no forwarding of calls via these trunks this will result in an error and the call might be lost or not be processed by the telco.

Note

The selection of the Trunk is not part of this guide and is handled by the administrator during the setup of the outbound rules. The simplest way to test this, would be to use a prefix where by prefix 0 selects trunk A and prefix 1 selects trunk B. The final outbound rule setup can have various ways for automatically achieving this - this is independent of the caller ID setup.

Scenario 1 - Same DID as Extension, Different Root

In this scenario we assume extension 100 has the need to show the below caller IDs:

0044 (20) 12345 -100 via trunk A

0049 (30) 66666 -100 via trunk B

and extension 120

0044 (20) 12345 -120 via trunk A

0049 (30) 66666 -120 via trunk B

In short, the internal extension number is equal to the external DID which should be presented but with a different national code, area code and root number (changes may apply to your setup or just a one-off change, it does not really matter). Therefore the setup should be like this:

Edit the extension 100 and under ‘Other’ set the outbound caller ID for that extension number. Below shown for extension 100. Repeat this step for all extensions that require this approach in your installation.

Open the trunk A (regardless if this is a SIP Trunk or PSTN gateway) and navigate to the ‘Outbound CID Formatting’ area.

Define one single rule whereby the ‘Source CID Pattern’ is set to (...) which defines a 3 digit number (matches 100 and 120). If you use a 2 digit or 4 digit extension number alter the dots to the remaining digits.Note: The ‘New Source CID Pattern’ depends on the caller ID format which is required by your trunk provider and may vary from one provider to another. Enquire in which number-format you need so send a caller ID to your provider.

Now open Trunk B and navigate to the same settings to define the other caller ID using the same approach.

Completed. The caller ID for extension 100 and 120 is now set based on the selected Trunk.

Scenario 2 - Different DID to Extension Number

In this scenario we assume extension 100 has the need to show the below Caller IDs (limit 15 extensions):

0044 (20) 12345 - 20 via trunk A

0049 (30) 66666 - 20 via trunk B

and extension 120

0044 (20) 12345 -30 via trunk A

0049 (30) 66666 -30 via trunk B

In short, the internal extension number is not equal to the external DID which should be presented. The number that appears though should always have the same DID. Therefore the setup should be like this:

For extension 100 set the outbound caller ID as ‘20’

Navigate to trunk A’s ‘Outgoing CID Formatting’ and set

Source CID Pattern (..)

New Source CID Pattern 00442012345\1

Repeat for trunk B

Source CID Pattern (..)

New Source CID Pattern 00493066666\1

Scenario 3 - No Static Relation Between Extension and DID

In this scenario we assume extension 100 has the need to show the below caller ID (limit 15 extensions):

0044 (20) 12345 - 20 via trunk A

0049 (30) 66666 - 30 via trunk B

and extension 120

0044 (20) 12345 -40 via trunk A

0049 (30) 66666 -50 via trunk B

In short, the internal extension number is not equal to the external DID and the DID is not the same on both trunks. This requires a bit more work as not a single extension can be used. This option is not recommended for configuring multiple extensions. Please see the setup below:

Overlap Match Protection

Due to a potential mapping overlap of caller IDs with the space holder (...) or (100) need an additional rule which must be situated at position one in the ‘Outbound CID Formatting’ to avoid unwanted re-writes. Below shown a sample for trunk B.

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